preloadResponse property

JSPromise<JSAny?> get preloadResponse

@AvailableInWorkers("service")

The preloadResponse read-only property of the FetchEvent interface returns a Promise that resolves to the navigation preload Response if navigation preload was triggered, or undefined otherwise.

Navigation preload is triggered if navigation preload is enabled, the request is a GET request, and the request is a navigation request (generated by the browser when loading pages and iframes).

A service worker can wait on this promise in its fetch event handler in order to track completion of a fetch request made during service-worker boot.

Implementation

external JSPromise<JSAny?> get preloadResponse;